At present, an organic electroluminescent element receives attention as a thin light-emitting material.
An organic electroluminescent element (so-called organic EL element) utilizing electroluminescence (Electro Luminescence: EL) of an organic material is a thin-film-type completely solid-state element that can emit light at a low voltage of approximately several volts to several ten volts, and has many excellent advantages such as high luminance, high light-emission efficiency, thin type and light weight. Accordingly, in recent years, the element has attracted attention, as surface emitting bodies such as: backlights for various kinds of displays; display boards for signboards, emergency lights and the like; and lighting sources.
The organic EL element as described above has a configuration in which a light-emitting layer composed of an organic material is arranged between two electrodes, and emitted light generated in the light-emitting layer is externally extracted through the electrode. Therefore, at least one of the two electrodes is constituted as a transparent electrode, and the emitted light is extracted from the transparent electrode side.
Note that the transparent electrode is also utilized not only for the organic EL element, but also as an electrode for a solar cell, a touch panel, a liquid display element, various light receiving elements, and the like. Furthermore, since the transparent electrode is usually a thin electrically conductive film, the transparent electrode is also used as a flexible electronic device by utilizing the small thickness.
In recent years, in the above electronic devices, the reduction in electric resistance has been required for making an area of the transparent electrode large. Therefore, in order to aim at lowering the electric resistance, there have been proposed a transparent electrode having a thin wire structure portion of an electrically conductive metal material and a translucent electrically conductive film (for example, refer to the following Patent Literature 1), and a configuration having an electrically conductive metal thin wire pattern formed by metal nanoparticles and an electrically conductive polymer-containing layer on the metal thin wire pattern (for example, refer to the following Patent Literature 2).